Field test kit reagent transferring system and method for using same

ABSTRACT

Chemical analytical field test kits which include narrow mouthed vials or ampules for containing precisely measured quantities of reagent solutions are sometimes difficult to use. This is because of the difficulty in emptying, i.e., quantitatively transferring, the reagent solution from the narrow mouthed container. Some, or all of the solution tends to bridge the opening and &#39;&#39;&#39;&#39;hang up&#39;&#39;&#39;&#39; in the container. A suitable means for eliminating this difficulty is disclosed. In a preferred embodiment, a test kit which utilizes a narrow mouthed glass vial also includes a short length of small diameter flexible tubing which is not substantially wetted by the reagent solution. Insertion of one end of the narrow diameter tubing into the opened analytical reagent vial, bending the other end of the flexible tubing back along the body of the vial, and pouring of the solution from the vial, while the tubing configuration remains fixed with respect to the vial, results in immediate delivery of all the reagent solution from the vial with substantially no risk of loss of drops of reagent solution, due to droplet scattering, or due to excess hold-up in the vial.

United States Patent Luks et al,

[451 Apr. 4, 1972 [54] FIELD TEST KIT REAGENT TRANSFERRING SYSTEM AND METHOD FOR USING SAME [72] Inventors: Kraemer D. Luks, South Bend, Ind.; Evan Jones, Evanston; Richard J. Krause, Ad-

[21] Appl. N0.: 52,424

Primary Examiner-Morris O. Wolk Assistant Examiner-Elliott A. Katz Anomey -Greist, Lockwood, Greenawalt and Dewey 5 7] ABSTRACT Chemical analytical field test kits which include narrow mouthed vials or ampules for containing precisely measured quantities of reagent solutions are sometimes difficult to use. This is because of the difficulty in emptying, i.e., quantitatively transferring, the reagent solution from the narrow mouthed container. Some, or all of the solution tends to bridge the opening and hang up" in the container. A suitable means for eliminating this difficulty is disclosed.

in a preferred embodiment, a test kit which utilizes a narrow mouthed glass vial also includes a short length of small diameter flexible tubing which is not substantially wetted by the reagent solution. Insertion of one end of the narrow diameter tubing into the opened analytical reagent vial, bending the other end of the flexible tubing back along the body of the vial, and pouring of the solution from the vial, while the tubing configuration remains fixed with respect to the vial, results in immediate delivery of all the reagent solution from the vial with substantially no risk of loss of drops of reagent solution, due to droplet scattering, or due to excess hold-up in the vial.

12 Claims, 7 Drawing Figures Patented April 4, 1972 3,653,839

' INVENTORS KRAEMER '0. LUKS EVAN JONES RICHARD J. KRAUSE v ATT FIELD TEST KIT REAGENT TRANSFERRING SYSTEM AND METHOD FOR USING SAME This invention relates to an improvement in field test kits which utilize narrow mouthed vials or ampules.

Integral vials, or ampules, are widely used and are eminently satisfactory for use as a container for precisely measured quantities of analytical reagent solutions which must be protected from atmospheric contamination, e.g., precisely measured volumes of 0.001 N. aqueous potassium hydroxide solution.

Such integral vials or ampules often have a narrow mouth portion, particularly the smaller sizes, and commonly include an extended sealed end portion, usually bulbous, extending beyond the mouth portion. Ampules are commonly prescored in the mouth region to facilitate opening of the ampule by merely breaking off the extended end portion. This can be done by holding the container portion vertically in one hand and bending the extended portion with the other hand, with the result that the end breaks off at the scored mouth. Quite commonly, these ampules are opened by holding the container portion vertically, holding the narrow scored mouth region against a sharp back-stop and smartly rapping the extended portion with a heavy object. To facilitate the breakingoff of the end portions, thus opening the ampules, the mouth region of the ampules is commonly drawn as narrow as possible. Thus, generally speaking, the narrower the mouth region, the better, in tenns of ease of opening such vials or ampules.

Such ampules have been extremelywidely used in the medical profession for use as containers for solutions intended for use in conjunction with hypodermic syringes. In such use of the ampuls, the relatively extremely narrow mouth does not constitute any particular disadvantage. The contained solution, e.g., a solution of a drug, is usually transferred into a hypodermic syringe by inserting a hypodermic needle through the relatively narrow mouth while holding the ampule vertical and withdrawing the solution into the syringe by withdrawing the hypodermic syringe piston.

The use of these extremely practical ampule-type containers in chemical field-test kits is highly desirable for many reasons. For example, these ampules are relatively inexpensive because of their widespread use in the medical profession, and, they are available in a large variety of sizes. Also, the technology of filling and sealing such ampules is already well developed and has proven to be commercially practical. In addition, these ampules can be sealed with an inert gas head space, by available technological procedures. Moreover, it is quite common to utilize glass as the construction material for these ampules and, once sealed, such containers provide virtually ideal protection of the enclosed solution against atmospheric contamination.

However, it has been found that the use of such ampules as sealed containers for quantitative reagent solutions in field test kits presents several serious problems. For example, it is essential that the enclosed solution be drainable therefrom with substantially quantitative precision. It is therefore essential that there be substantially no excess solution hold-up in the vial or container. It is to be understood that, naturally, some of the solution in an ampule may wet the walls of an ampule, and, will thus be held up in the ampule even after delivery therefrom, of all the liquid which can be drained in a reasonable time, e.g., 10 seconds. However, it has been found that some, or all, of the drainable reagent solution occasionally remains in the ampule, particularly when relatively small sized ampules are utilized, even though the ampule is upended in a position for pouring the reagent solution out of the ampule into a reactor vessel. The technician using the test kit must then tap or shake the inverted ampule in an attempt to deliver the precisely measured quantity of reagent solution from the ampule into a reactor vessel. This difficulty presents a three-fold disadvantage, namely, the annoyance and delay encountered in draining the solution from the ampule, the risk of loss of precision due to excess hold-up of a bridging portion of the solution in the ampule, and thirdly the risk of loss of one or more drops of solution by scattering while tapping or shaking the bridging solution from the ampule.

' It would be highly desirable to provide a field-test kit for quantitative and semi-quantitative testing, under non-laboratory conditions, which kit utilizes a narrow-mouthed ampule containing precisely measured predetermined quantities of reagents, which includes means for rapidly, conveniently, and reliably, delivering a precise, predetermined quantity of solution from the ampule. It would also be desirable to provide an analytical field test kit which eliminates the risk of loss of indeterminate quantities of reagent solution during the necessary transferring thereof from ampules.

Accordingly, it is an object of this invention to provide a means and method for rapidly, reliably and precisely transferring and draining predetermined quantities of analytical reagent solution from narrow-mouthed vials or ampules.

It is also an object of this invention to provide a means and method for permitting a vial or ampule to continue to drain while the operator performs other steps in the analytical procedure.

It is another object of this invention to provide a combination of elements constituting a field-test kit, the use of which does not require that an operator hold a container over a reactor vessel for extended periods in order to provide some standard drainage time.

These and other objects which will be apparent hereinafter are all accomplished in accordance with this invention, which is described generally, and in detail hereinafter, and with the aid of the drawings, in which:

FIG. 1 is a perspective view of a quantitative analytical test kit improved in accordance with this invention.

FIG. 2 is a plan view of the test kit illustrated in FIG. 1

FIG. 3 is an elevational view illustrating the transfer of solution from an ampule to a reactor vessel in accordance with this invention.

FIGS. 4a, 4b, 4c, and 4d show a preferred method of transferring in accordance with this invention.

As illustrated in the attached figures, test kit, designated generally at 10, includes carton assembly 12 which includes body portion 14 and hinged lid 16. Lid 16 andcarton body portion 14 include conventional lid securing means 18. Carton body portion 14 receives tightly fitting component retainer insert 20 which includes means for retaining and separating by divider 22 a relatively large, capped reactor vessel 24, an analytical reagent containing ampul 26, an empty, capped oil measuring vial 28 and a capped, sealed, solvent container 30.

'- Retainer insert 20 thus includes a cut-out inverted V"shaped receive their corresponding components for preventing substantial lateral movement thereof.

Insert 20 can be tipped upwardly at mouth side 40 of carton 12 for speedy removal of the component by an operator by manually grasping one of the elements 26, 28, or 30, near mouth side 40 and lifting. This causes the entire insert to tip upwardly thereby permitting removal of components 26, 28, 30 by axially sliding the respective components out of their respective retainer cut-out providing the cut-outs are large enough to permit caps to pass axially. Insert 20 is conveniently retained in the tipped-up position for removal of the respective components by pressing sides 42 inwardly against the upwardly tipped insert 20.

Alternatively components 26, 28, and 30 can be removed by pivoting the component within its cut-out attachment to of flexible plastic, and is preferably made from a plastic, or other material, which is not substantially wetted by the reagent solution within ampule 26. The illustrated test kit is well suited to a practical application of the analytical test method disclosed in US. Pat. No. 3,510,260, which patent is assigned to a common assignee. For example, ampule 26 can contain a precisely measured predetermined quantity of 0.001 N KOl-l. Capped measuring vial 28 can be used to measure a specific quantity of oil to be tested. Sealed container 30 can be used to contain an appropriate titration solvent for use in accordance with the test method described and claimed in the aforesaid patent, e.g., a titration solvent composed of 50 percent toluene (reagent grade), 49.5 percent isopropyl (reagent grade) and 0.5 percent distilled water (all percentages being based on volume). The illustrated test kit, therefore, is ideally suited for a relatively precise determination of whether or not an oil sample had an acid level exceeding a predetermined threshold level. For example, ampule 26 can be provided with enough 0.001 N KOH to provide the stoichiometric equivalent of an acid number of 0.05 in the quantity of oil delivered from measuring vial 28, acid number being the number of mg. of KOH required to react with all the acid in 1 gram.

To perform a test of an oil sample with a kit such as that illustrated in the attached drawings, ampule 26 is first removed from kit 10, and opened. It is noted that ampule 26 includes constricted neck portion 48 and bulbous end portion 50. It is preferred that neck 48 be pro-scored, e.g., scratched with a file at a point corresponding to the narrowest diameter thereof. Ampule 26 is held vertically, i.e., with end 50 extend ing perpendicularly upward, neck 48 is placed against a sharp backstop and end 50 is smartly rapped with a relatively heavy object. This causes end 50 to break from body portion 46 at scored neck 48, to provide an opened ampule, e.g., 52, 53. It is apparent that the open mouth 54 is relatively narrow. Occasionally liquid 56 within opened ampule 52, 53 would bridge opened mouth 54 with the result that liquid 56 remained hung-up in ampule 52. In accordance with one embodiment of the use of this invention, illustrated inFlG. 3, one end 60 of vent tube 44 is inserted through mouth 54 upwardly through the body of liquid 56. The other end 62 is bent around a flex zone 64 to extend upwardly above the upper level 66 although, if tube 44 is not wetted by liquid 56, it is not necessary that end 62 be extended above level 66. This insertion of tube 44 vents head space 68 whereby the hydrostatic head of liquid 56 forces liquid 56 to flow from mouth 54 into reactor 24.'

It is noted further that, in accordance with a preferredembodiment of this invention in which tube 44 is not wetted by liquid 56 droplets 70 leaving mouth 54 do not adhere to tube 44 and do not run downwardly along tube 44, but rather descend directly into reactor vessel 24. Hence, in accordance with this embodiment, the danger of laterally projecting droplets away from the mouth 72 of reactor 24 from flex region 64 is substantially eliminated. End 62 of tube 44 makes for easy manipulation of tube 44.

In a particularly preferred embodiment of the apparatus and method of this invention, inside diameter of mouth 72 of reactor vessel 24 is slightly less than the sum of the outside diameter of body portion 46, of ampule 53 plus the outside diameter of tube 44. In this latter mentioned preferred embodiment, a particularly advantageous operating relationship exists. Thus,

as illustrated in FIGS. 4a, 4b, 4c, and 4d, end 60 of tube 44' is inserted to approximately the bottom of vertically standing, opened ampule S3, and tube 44' is flexed around the flex zone 64' whereby extending end portion 62 either hangs downwardly or is held adjacent body portion 53, as illustrated in FIG. 4a, by the operators left hand, for example. With his right hand, for example, the operator can invert reactor 24' over the assembly illustrated in FIG. 4a to bring mouth 72' downwardly over body portion 53 and extending portion 62 of tube 44. Using either one or both hands the operator can then invert the three components illustrated in FIG. 40 to up end ampule 53 over reactor vessel 24. By providing a combination of components having the respective diameters in the relationship defined above extended end portion 62 of flexible tubing 44 is slightly compressed between opened ampule 53 and the mouth 72' of reactor vessel 24'. This binding action permits ampule 53 to be supported as illustrated in FIG. 4d, within the mouth 72 of reactor vessel 24. This frees the operators hands to perhaps pour an oil sample into measuring vial 28, or begin unsealing closed, sealed solvent-container 30. The quantity of solution 56, 56' within ampule 26 is predetermined to deliver a predetermined stoichiometric amount of reagent to reactor vessel 24, 24'. Alter a reasonable, short period of time lapses, up-ended opened ampule 53, 53" is taken away from mouth 72, 72' of reactor vessel 24, 24'. An oil sample is poured into unstoppered vial 28 which is used as a measuring vial. The vial is preferably provided with a cap 75 to assure that the measuring chamber of vial 28 remains uncontaminated during storage of kit 10.

The measured quantity of oil-in measuring vial 28 is then added to vessel 24, 24. I

Solvent, which has been sealed in bottle 30 is then poured into the reactor vessel 24. A suitable indicator must be provided, for example, phenolphthaleine. In the illustrated embodiment, if phenolphthaleine is used, as the indicator, oil samples containing less than the predetermined stoichiometric threshold level of acid, e.g., an acid number 0.05, will not provide sufficient acidity to change the pink color of the phenolphthaleine. Thus, after all the previously described liquids are added to the reactor vessel 24, and that vessel is capped and shaken vigorously, if the lower layers remain pink, the test reveals that the level of acid is less than 0.05. To further bracket the actual acid content in the sample, reactor vessel 24 can be reopened, and a second equal sample of oil, measured from measuring vial 28, can be added thereto. Upon recapping and reshaking reactor vessel 24 disappearance of the pink color will indicate that the sample has an acid number between 0.025 and 0.05 acid, whereas retention of the pink color indicates the acid number of the sample tested was less than 0.025. If, after a third equal sample is added to reactor 24, the color changes, it will be indicated that the acid content of the sample is between one-third and one-half of the threshold level, e.g., between0.0l67 and 0.025 in the illustrated embodiment. If the'color change does not occur until after the addition of a fourth sample, it will be indicated that the acid content of the sample is between one-quarter and one-third of the threshold level, e.g., between 0.0125 and 0.0167 in the illustrated embodiment, and so on. 7

Thus, the kit 10 must include a reactor vessel'having a volume sufficient to accomodate the contents of containers 26, 28, and 30, andto provide sufficient head space above said contents to permit adequate mixing thereof, when container 24 is capped and shaken.

It is preferred however, that reactor 24 be large enough to accomodate said contents, and in addition, accomodate multiple samples, i.e., preferably at least four samples, as measured by container 28, in those embodiments in which test kit 10 is intended for use for the purpose of bracketing actual acid concentrations and the like, as compared to merely determining whether or not the concentration is above or below some predetermined threshold concentration.

The flexible, small diameter tube which is used to vent the capsule in accordance with a preferred embodiment of this invention, is made from any reagent-inert material, preferably from a material which is not substantially wetted by the reagent solution. For example, a preferred narrow diameter flexible tubing for use in conjunction with a small-mouthed ampule containing dilute aqueous potassium hydroxide solutions is a No. 20, i.e., 0.034 inch'LD. black vinyl tubing. This tubing is considered to have a substantially ideal inside diameter because, surprisingly enough, none of the reagent solution enters the bore of the tubing as the end of the tubing is inserted into the reagent solution, and consequently no loss in precision occurs as a consequence of insertion of the vinyl tubing into the reagent solution for transferring from the ampule. in

accordance with this invention, the tubing should have less than 0.05 inch I.D. Generally spe king, black vinyl tubing in the standard sizes ranging from No. 18 (0.042 inch I.D.) through No. 24 (0.022 inch ID.) is eminently satisfactory for use in accordance with this invention. The inside diameter of the tubing must be large enough to permit venting of air into the ampule during drainage of reagent solution therefrom. However, if the inside diameter of the tubing is too large the result is unsatisfactory because reagent solution would tend to enter the bore of the tubing with the result that, upon inversion, that quantity of solution would not be delivered into the reactor vessel. For example, to illustrate, by contrast, a venting device which is not in accordance with this invention, the

. use of glass tubing with a one-sixteenth inch inside diameter,

having a sharp V bend at a distance from one end of the glass tubing sufficient to permit that end to be inserted into a capsule and to extend to the bottom of the capsule proved totally unsatisfactory for use in venting the capsule to facilitate transferring of the precise predetermined quantity of 0.001 N potassium hydroxide from the capsule. First of all, a substantial portion of the reagent solution entered the bore of the glass tubing. This entry is believed to be a result of a combination of factors, e.g., the fact that the inside diameter of the glass tubing was too large, and secondly that the particular test solution tested wetted the glass, thereby facilitating movement of the solution into the bore of the tube. Moreover, because the reagent solution wetted the outside, as well as inside of the glass tubing, the solution leaving the mouth of the capsule drained along the external, extending portion of the glass tubing when the assembly was up-ended for pouring and some drops of the solution were projected virtually horizontally from the bottom of the tubing at the sharp V bend with substantial risk of loss of solution from scattering. Also, when the assembly was up-ended, liquid drained into the bottom of the V within the tube and was not delivered to the reactor vessel.

The entry of small quantities of reagent into very narrow inside diameter tubing, i.e., less than 0.05 inches has proven to be tolerable, because of the fact that the narrow inside diameter passageway of the tubing is sufficiently aspirated or swept by air during the draining of the ampule, and the small quantity of reagent solution is conveyed back into the interior of the ampule itself.

Examples of commercially available flexible tubing which are eminently satisfactory for use in accordance with this invention include RESINITE Hl-HEAT'IOS, and 105C tubing (T.M. The Borden Chemical Company). This tubing is available in all standard sizes, wall thicknesses as specified. This tubing is made from high-heat resistant vinyl materials, is chemically inert to an extremely broad spectrum of reagent solutions, and is substantially not wetted by an extremely broad spectrum of reagent solutions, e.g., dilute aqueous hydroxide solutions. The use of the narrow diameter flexible tubing in accordance with this invention is particularly advantageous inasmuch as there is substantially no risk of breakage of the ampule vent tube during handling, for example during the loading of the kit package, during the distribution and/or shipping of the kit packages, or during the use of the kit in the field.

Nonetheless, the ampule venting means for use in accordance with this invention is not necessarily limited to flexible plastic materials, although flexible plastic materials are vastly preferred. Non-wettable glass tubing in V configuration can be used providing its inside diameter is sufficiently small. An example of a suitable non-wettable glass is a silicone glass tubing drawn to an inside diameter of less than 0.05 inch. Needless to say, in accordance with this preferred embodiment, the glass should be silicone-coated along the walls of the inner passageway, as well as on its outer surfaces.

The most preferred embodiment, however, utilizes a flexible plastic tubing which is only slightly compressible, in combination with an ampule and a reactor vessel having certain dimensional relationships referred to above. In accordance with the most preferred embodiment of this invention, the dimensional relationships referred to are achieved when the mouth of the reactor vessel has inside diameter D,, and when the sum of the outside diameter (D of the ampule, and the outside diameter of the tubing (D is just slightly greater than D,. When this dimensional relationship exists between the respective elements of the combination of this invention, the vented ampule assembly can be up-ended into the mouth of the reactor vessel and remain supported in that position for any desired period of time as illustrated in the drawings at FIG. 4d, without requiring the operator to hold the members.

The quantity of reagent solution placed in the ampule is that predetermined quantity which will deliver the desired predetermined quantity of reagent. It is apparent that the embodiments utilizing a tubing which is wetted by the reagent requires slightly more solution to deliver the desired amount, than an embodiment using a non-wettable tube.

In the particularly preferred method illustrated in FIGS. 4a, b, c, and d, it is noted that it is impossible to laterally project droplets of reagent solution 56 out of vessel 24' during inversion of the mated containers, even if solution 56 were to wet tube 44, since ampule 53' and tube are well within mouth 72' of vessel 24' during the inversion.

We claim:

1. A method for analyzing for a threshold concentration of a chemical in a sample comprising the steps placing a predetermined measured quantity of the sample in a reaction vessel, adding a predetermined quantity of reagent solution, and a color indicator responsive to predetermined concentrations of the reagent, in which method the predetermined quantity of reagent solution is transferred from an ampule which has a break-off cap and a constricted mouth, said method comprising the steps breaking off the end of the ampule, inserting one end of a small inside diameter tube into the ampule and extending said end of said tube to a position near the bottom of the ampule while maintaining the other end of the tube external to the ampule, said diameter being too small to permit a substantial quantity of said reagent solution to flow therein, extending the other end of the tube towards the bottom of the ampule, inverting the ampule, and pouring the contents of the ampule into the reaction vessel.

2. The improvement of claim 1 in which the tube is made from a material which is not wetted by said reagent solution.

3. A test kit, comprising: a package; a reactor vessel removably mounted in said package, said vessel having a mouth with an inside diameter D; an ampule removably mounted in said package, said ampule containing a precisely measured, predetermined quantity of reagent solution, said ampule having a break-off top portion and a body portion, the body portion having an outside diameter-of D said package including a length of flexible tubing having an outside diameter of D and an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein; and wherein the sum of D plus D is slightly more than D, whereby the ampule and said tube can be inserted into the mouth of the reactor vessel with only slight compression of the tube, said slight compression being insufiicient to close the conduit of the tube, and whereby the ampule and tube can remain in a self-supported, inverted position in the mouth of said reactor vessel.

4. A test kit as in claim 3, wherein the length of flexible tubing is at least twice as great as the length of said body portion.

5. A test kit as in claim 3 wherein the sum of D plus D is slightly more than D, whereby the container and said tube can be inserted into the mouth of the reactor vessel with only slight compression of the tube, said slight compression being insufficient to close the conduit of the tube, and whereby the container and the tube can remain side by side in a self-supported, inverted position in the mouth of said reactor vessel.

6. A method of transferring quantitatively a precisely measured predetermined quantity of reagent solution from an ampule having a break-off end portion and a constricted mouth portion comprising the steps: breaking off the end portion of the ampule, inserting one end of a length of flexible tubing into the mouth of the ampule and moving said end of said tubing to a position adjacent the bottom of the ampule, said tubing having an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein, bending a portion of the tube which extends out of the mouth of said ampule rearwardly in the general direction of the inserted portion of the tube, and while maintaining the tube in that position with respect to the ampule, draining the contents of the ampule therefrom by lowering the mouth of the ampule below the contents therein.

7. A test method of bracketing the concentration of a component in a fluid sample at a test site in the field under nonlaboratory conditions comprising the steps placing a predetermined amount of reagent solution inan ampule, said ampule having a break-off cap and a constricted mouth; sealing the ampule; conveying the sealed ampuleto said test site; transferring said solution from the ampule to a reaction vessel, said transferring comprising the steps breaking off the end of the ampule, inserting one end of the small inside diameter tubing into the ampule and extending said end of said tube to a position near the bottom of the ampule, while maintaining the other end of the tubing external to the ampule, said diameter being too small to permit a substantial quantity of said reagent solution to flow therein extending the other end of the tube toward the bottom of the ampule, inverting the ampule, and pouring all the contents of the ampule into the reaction vessel, said predetermined amount of reagent being that amount which provides that a specific stoichiometric equivalent of the reagent be delivered from said ampule to said reaction vessel in the aforesaid steps; mixing an indicator with said reagent solution, said indicator being a chemical which undergoes a color change when the stoichiometric quantity of reagent in the reactor vessel is consumed; subsequently incrementally adding to the reactor vessel equal predetermined quantities of said fluid sample, said predetermined quantities having been selected so that each individual quantity would provide an amountof said component stoichiometrically equivalent to said specific stoichiometric equivalent if said component were present in the sample at a predetermined threshold concentration; and thoroughly mixing each of said predetermined quantities of sample with the contents of the reactor vessel between each of said incremental additions; said incremental adding and mixing steps continuing until the indicator changes color, whereby a color change upon adding and mixing the first incremental addition of sample indicates the concentration of the component in said sample is greater than the threshold concentration, and whereby a color change after the adding and mixing of more than one incremental addition of sample indicates the concentration of said component in said sample is greater than (l/N X threshold concentration), and less than (l/( N1) threshold concentration),

N being a whole number greater than I and equal to the total number of said predetermined quantities which were incrementally added.

8. A method for analyzing for a threshold concentration of a chemical in a sample comprising the steps placing a predetermined measured quantity of the sample in a reaction vessel, adding a predetermined quantity of reagent solution, and a color indicator responsive to predetermined concentrations of the reagent, in which method the predetermined quantity of reagent is transferred from a container having a constricted mouth, said method comprising the steps inserting one end of a small diameter flexible tube into the mouth of the container and extending said end of said tube to a position near the bottom of the container, said tube having an inside diameter too small to permit a substantial quantity of said reagent solution to flow therein bending the other end of the tube toward the bottom of the container, inverting the container, and pouring the contents of the container into the reaction vessel.

9. A method of transferring quantitatively a precisely measured predetermined quantity of reagent solution from a container having a constricted mouth rtion comprising the steps: inserting one end of a length 0 flexible tubing into the mouth of the container and moving said end of said tubing to a position adjacent the bottom of the container, said tubing having an inside diameter too small to permit a substantial quantity of said reagent solution to flow therein, bending a portion of the tube which extends out of the mouth of the container rearwardly in the general direction of the inserted portion of the tube, and while maintaining the tube in that position with respect to the container, draining the contents of the container therefrom by lowering the mouth of the container below the contents therein.

10. A test kit, comprising: a package; a reactor vessel removably mounted in said package, said reactor vessel having a mouth with an inside diameter D; a sealed container removably mounted in said package, said sealed container containing a precisely measured, predetermined quantity of reagent solution, said sealed container having a body portion with an outside diameter of D said package including a length of flexible tubing which has an inside diameter which is too small to permit a substantial quantity of said solution to flow therein, said flexible tubing having an outside diameter of D wherein the sum of D plus D is such that the ampule and said tube can be. inserted side by side into the mouth of the reactor vessel.

11. A test kit as in claim 10 wherein said container is an ampule with a break-off tip.

12. A test kit, comprising; a package; a reactor vessel removably mounted in said package; an ampule removably mounted in said package, said ampule containing a precisely measured predetermined quantity of reagent solution, said ampule having a constricted mouth; and a length of flexible tubing having an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein, said tubing beingsufficiently long for a portion thereof to be inserted into said ampule to a position adjacent to the bottom of the ampule leaving an extending portion thereof extending outwardly of said constricted mouth, said extending portion being sufficiently long to be bent rearwardly in the general direction of the inserted portion. 

2. The improvement of claim 1 in which the tube is made from a material which is not wetted by said reagent solution.
 3. A test kit, comprising: a package; a reactor vessel removably mounted in said package, said vessel having a mouth with an inside diameter D; an ampule removably mounted in said package, said ampule containing a precisely measured, predetermined quantity of reagent solution, said ampule having a break-off top portion and a body portion, the body portion having an outside diameter of D2; said package including a length of flexible tubing having an outside diameter of D3 and an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein; and wherein the sum of D2 plus D3 is slightly more than D, whereby the ampule and said tube can be inserted into the mouth of the reactor vessel with only slight compression of the tube, said slight compression being insufficient to close the conduit of the tube, and whereby the ampule and tube can remain in a self-supported, inverted position in the mouth of said reactor vessel.
 4. A test kit as in claim 3, wherein the length of flexible tubing is at least twice as great as the length of said body portion.
 5. A test kit as in claim 3 wherein the sum of D2 plus D3 is slightly more than D, whereby the container and said tube can be inserted into the mouth of the reactor vessel with only slight compression of the tube, said slight compression being insufficient to close the conduit of the tube, and whereby the container and the tube can remain side by side in a self-supported, inverted position in the mouth of said reactor vessel.
 6. A method of transferring quantitatively a precisely measured predetermined quantity of reagent solution from an ampule having a break-off end portion And a constricted mouth portion comprising the steps: breaking off the end portion of the ampule, inserting one end of a length of flexible tubing into the mouth of the ampule and moving said end of said tubing to a position adjacent the bottom of the ampule, said tubing having an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein, bending a portion of the tube which extends out of the mouth of said ampule rearwardly in the general direction of the inserted portion of the tube, and while maintaining the tube in that position with respect to the ampule, draining the contents of the ampule therefrom by lowering the mouth of the ampule below the contents therein.
 7. A test method of bracketing the concentration of a component in a fluid sample at a test site in the field under non-laboratory conditions comprising the steps placing a predetermined amount of reagent solution in an ampule, said ampule having a break-off cap and a constricted mouth; sealing the ampule; conveying the sealed ampule to said test site; transferring said solution from the ampule to a reaction vessel, said transferring comprising the steps breaking off the end of the ampule, inserting one end of the small inside diameter tubing into the ampule and extending said end of said tube to a position near the bottom of the ampule, while maintaining the other end of the tubing external to the ampule, said diameter being too small to permit a substantial quantity of said reagent solution to flow therein extending the other end of the tube toward the bottom of the ampule, inverting the ampule, and pouring all the contents of the ampule into the reaction vessel, said predetermined amount of reagent being that amount which provides that a specific stoichiometric equivalent of the reagent be delivered from said ampule to said reaction vessel in the aforesaid steps; mixing an indicator with said reagent solution, said indicator being a chemical which undergoes a color change when the stoichiometric quantity of reagent in the reactor vessel is consumed; subsequently incrementally adding to the reactor vessel equal predetermined quantities of said fluid sample, said predetermined quantities having been selected so that each individual quantity would provide an amount of said component stoichiometrically equivalent to said specific stoichiometric equivalent if said component were present in the sample at a predetermined threshold concentration; and thoroughly mixing each of said predetermined quantities of sample with the contents of the reactor vessel between each of said incremental additions; said incremental adding and mixing steps continuing until the indicator changes color, whereby a color change upon adding and mixing the first incremental addition of sample indicates the concentration of the component in said sample is greater than the threshold concentration, and whereby a color change after the adding and mixing of more than one incremental addition of sample indicates the concentration of said component in said sample is greater than (1/N X threshold concentration), and less than (1/(N-1) X threshold concentration), N being a whole number greater than 1 and equal to the total number of said predetermined quantities which were incrementally added.
 8. A method for analyzing for a threshold concentration of a chemical in a sample comprising the steps placing a predetermined measured quantity of the sample in a reaction vessel, adding a predetermined quantity of reagent solution, and a color indicator responsive to predetermined concentrations of the reagent, in which method the predetermined quantity of reagent is transferred from a container having a constricted mouth, said method comprising the steps inserting one end of a small diameter flexible tube into the mouth of the container and extending said end of said tube to a position near the bottom of the container, said tube having an inside Diameter too small to permit a substantial quantity of said reagent solution to flow therein bending the other end of the tube toward the bottom of the container, inverting the container, and pouring the contents of the container into the reaction vessel.
 9. A method of transferring quantitatively a precisely measured predetermined quantity of reagent solution from a container having a constricted mouth portion, comprising the steps: inserting one end of a length of flexible tubing into the mouth of the container and moving said end of said tubing to a position adjacent the bottom of the container, said tubing having an inside diameter too small to permit a substantial quantity of said reagent solution to flow therein, bending a portion of the tube which extends out of the mouth of the container rearwardly in the general direction of the inserted portion of the tube, and while maintaining the tube in that position with respect to the container, draining the contents of the container therefrom by lowering the mouth of the container below the contents therein.
 10. A test kit, comprising: a package; a reactor vessel removably mounted in said package, said reactor vessel having a mouth with an inside diameter D; a sealed container removably mounted in said package, said sealed container containing a precisely measured, predetermined quantity of reagent solution, said sealed container having a body portion with an outside diameter of D2; said package including a length of flexible tubing which has an inside diameter which is too small to permit a substantial quantity of said solution to flow therein, said flexible tubing having an outside diameter of D3; wherein the sum of D2 plus D3 is such that the ampule and said tube can be inserted side by side into the mouth of the reactor vessel.
 11. A test kit as in claim 10 wherein said container is an ampule with a break-off tip.
 12. A test kit, comprising; a package; a reactor vessel removably mounted in said package; an ampule removably mounted in said package, said ampule containing a precisely measured predetermined quantity of reagent solution, said ampule having a constricted mouth; and a length of flexible tubing having an inside diameter which is too small to permit a substantial quantity of said reagent solution to flow therein, said tubing being sufficiently long for a portion thereof to be inserted into said ampule to a position adjacent to the bottom of the ampule leaving an extending portion thereof extending outwardly of said constricted mouth, said extending portion being sufficiently long to be bent rearwardly in the general direction of the inserted portion. 